JPH05186557A - Polyurethane elastomer and its production - Google Patents

Abstract

PURPOSE:To obtain stably the title elastomer of excellent properties by adding a plurality of specified compounds to an elastomer based on a polyurethane obtained by using a polyol, a diisocyanate and a diamine as the main reactants. CONSTITUTION:The title elastomer is prepared by adding a sec. amine (e.g. diethylamine), a ketoimineamine and/or an aldoimineamine (e.g. a ketoimineamine which is a reaction product between equimolar amounts of acetone and ethylenediamine) to an elastomer based on a polyurethane obtained by using a polyol (e.g. polytetramethylene ether glycol), a diisocyanate (e.g. 4,4'-diphenylmethane diisocyanate) and a diamine (e.g. ethylenediamine) as the main reactants.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane elastic body and a method for producing the same. More specifically, the elastic modulus,
The present invention relates to a polyurethane elastic body having excellent physical properties such as foldability and having small fluctuations in the physical properties, and a method for producing the same.

[0002]

2. Description of the Related Art U.S. Pat. No. 3,55,55 has been proposed as an attempt to improve the elastic properties of polyurethane elastic materials by increasing their molecular weight.
No. 7,044 and Japanese Patent Publication No. 46-14473 are known. In these techniques, a polyurethane solution having an isocyanate group blocked with a low-molecular-weight secondary amine and an amino group as an end group is spun and heated in a post-processing step to cause an exchange reaction between both end groups to achieve high performance. It uses the technology of molecular weight conversion.

In order to obtain a polyurethane elastic body by these methods, a prepolymer solution of isocyanate having both end groups is reacted with a mixed solution of a primary diamine and a secondary monoamine in an amount equal to or more than the isocyanate group of this prepolymer. And the chain extension reaction is performed. The obtained polyurethane elastic body solution is further subjected to spinning and heating to further increase the molecular weight in the post-processing step. The difference between the molecular weight of the polyurethane elastic body in this polyurethane elastic body solution and the molecular weight of the polyurethane elastic body after spinning and post-processing is "post-polymerization".
The degree of “post-polymerization” is defined by the ratio of the primary diamine and secondary monoamine used in the chain extension reaction.

Although the physical properties of the polyurethane elastic body are improved by these methods, the "post-polymerization" of the polyurethane elastic body is improved.
The difference of appears as a change in physical properties. Further, the amino group which is the terminal group of the polyurethane elastic body and the organic isocyanate group blocked with the secondary amine react even at room temperature. Therefore, when it is spun and wound as cheese, the molecular weight of the threads of cheese with different ages is different even at room temperature,
Even with the same cheese, a situation may occur in which the molecular weight of the yarn differs between the inner layer and the outer layer of the cheese, which affects changes in the physical properties of the yarn.

On the other hand, a method of using ketoimine amine or aldimine amine for producing a polyurethane elastic body is known. JP-A-53-24396, JP-A-60-60
JP-A-161417 and JP-A-63-154719 propose a method for producing a polyurethane elastic body using ketoimine amine and aldoimine amine. These technologies are different in that water is removed from the ketoimine amine and aldimine amine used, that water is not added, and that water is added, and that a solvent is not used when manufacturing the polyurethane elastic body. Ketoimine amine and aldimine amine are used in place of diamine in order to slow down the reaction rate between the isocyanate group of the polymer and the diamine.

[0006]

The object of the present invention is that the polyurethane elastomer obtained by the conventional method "post-polymerizes" at room temperature in addition to the heating conditions during the post-processing step.
To provide a method for producing a polyurethane elastic body that "post-polymerizes" only under heating conditions, that is, a method for easily producing a polyurethane elastic body having excellent physical properties and less physical property fluctuations than those obtained by conventional methods. is there.

[0007]

That is, the present invention provides a method for producing a polyurethane elastic body by subjecting a prepolymer obtained from a polyol and an excess amount of an organic diisocyanate to a chain extension reaction with an organic diamine to produce a secondary terminator as a secondary terminating agent. A polyurethane elastic body characterized by using a monoamine and a ketoimine amine and / or an aldoimine amine, and a method for producing the same. Ketoimine amine and aldoimine amine are represented by the following general formula (A),
A polyurethane elastic body and a method for producing the same, which are a ketoimine reaction product of a ketone and a diamine and an aldoimine reaction product of an aldehyde and a diamine, which are represented by (B) and (C). H ₂ N-R-NH ₂ (A) H ₂ N-R-N = R ₁ (B) R ₁ = N-R-N = R ₁ (C) [wherein R has 2 to 18 carbon atoms , And -N (X)-
(Wherein, -X is _{-H, -CH 3, -C 2 H} 5, -C 3 H
_7, or represents a -C ₄ H _9. A divalent aliphatic or alicyclic group, wherein R ₁ represents an aliphatic group which can be obtained by removing oxygen from a ketone or aldehyde having 2 to 8 carbon atoms. ]. The present invention will be described in more detail below.

In the polyurethane elastic material of the present invention, a prepolymer of an isocyanate at both ends consisting of a polyol and an excess of organic diisocyanate is used in a polar solvent such as N, N-dimethylacetamide, N, N-dimethylformamide or hexamethylenephosphylamide. By using a secondary amine and a ketoimine amine and / or an aldimine amine obtained by reacting an organic diamine with a ketone or an aldehyde as a terminal terminating agent when a polymer is dissolved and subjected to a chain extension reaction with an organic diamine. ,Obtainable.

As the polyol used in the present invention, any polyol such as polyoxyethylene ether glycol, dihydroxy-terminated polyethylene adipate, polybutylene adipate, and polycaprolactam which are used in the production of polyurethane elastic bodies can be used. Any molecular weight may be used, but from the viewpoint of the physical properties of the polyurethane elastic body, a molecular weight of 1000 to 3000 is desirable.

As the organic diisocyanate, 4,4 '
Aromatic diisocyanates such as diphenylmethane diisocyanate, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate are desirable.

These polyols and an organic diisocyanate are mixed in a molar ratio of 1.5 to 3.0 so that the organic diisocyanate is in excess, and reacted at a temperature of 60 to 120 ° C. to obtain a prepolymer. At this time, two or more kinds of polyols and organic diisocyanates can be copolymerized within a range that does not impair the physical properties of the polyurethane elastic body obtained. Also, low molecular weight diols such as ethylene glycol, propylene glycol and butanediol can be copolymerized.

The prepolymer thus obtained was mixed with 4
After cooling to 0 ° C. or below, N, N-dimethylacetamide,
A prepolymer solution is obtained by dissolving in a polar solvent such as N, N-dimethylformamide or hexamethylenephosphylamide.

A chain extension reaction is carried out by reacting this prepolymer solution with an organic diamine dissolved in a polar solvent such as N, N-dimethylacetamide, N, N-dimethylformamide and hexamethylenephosphamide.

As the organic diamine, ethylenediamine,
1,2-Cyclohexanediamine, 1,3-cyclohexanediamine, 1,4′-cyclohexanediamine, propylenediamine, hydrazine and the like are preferable.

Simultaneously with the reaction with this organic diamine and / or
Alternatively, a terminal terminating reaction is carried out before and after with ketoimine amine and / or aldimine amine and a secondary amine.

These ketoimine amines and aldimine amines are disclosed in JP-A-53-24396 and JP-A-60-16.
1417, JP-A-63-154719, etc., it can be easily obtained by heating and reacting a ketone or aldehyde such as acetone or methyl ethyl ketone with an organic diamine such as ethylenediamine or propylenediamine. it can.

As the secondary amine, diethylamine,
Diisopropylamine, di-n-butylamine, dicyclohexylamine and the like are preferable.

In order to extend the chain of the prepolymer solution with the organic diamine in a continuous reaction, the prepolymer solution is adjusted so that the total equivalent of the amine is more than the equivalent of the isocyanate of the prepolymer. A polymer is obtained by vigorously stirring a mixed solution of ketoimine amine and secondary amine with a mixer or the like. At this time, a part or all of the ketoimine amine and the secondary amine may be reacted before and / or after the reaction with the organic diamine.

In order to carry out the chain extension reaction in a batch system, a mixture of an organic diamine, a ketoimine amine and a secondary amine, which is adjusted so that the total equivalent of amine is less than the equivalent of isocyanate of the prepolymer, in the prepolymer solution. A solution is added to carry out a chain extension reaction, and a terminal termination reaction is carried out with a mixed solution of ketoimine amine and secondary amine. At this time, a part of the ketoimine amine and / or the secondary amine may be preliminarily reacted before the chain extension reaction, or the ketoimine amine and / or the secondary amine may not be present in the chain extension reaction agent.

Also in this other method, any method may be used as long as the secondary amine and the ketoimine amine and / or the aldimine amine react with the isocyanate while the isocyanate group of the prepolymer remains. be able to.

The polyurethane elastic body solution thus obtained is spun or cast to produce a thread or film. Then, by heating these yarns or films, an exchange reaction between the isocyanate group blocked with the secondary amine and the isocyanate group blocked with the ketoimine amine and / or the aldoimine amine occurs to cause "post-polymerization". Higher molecular weight.

JP-A-53-24396, JP-A-6-26
Nos. 0-161417 and JP-A-63-154719 propose a method for producing a polyurethane elastic body using ketoimine amine and aldoimine amine. In both cases, ketimine amine or Aldiimine amine is used to react an isocyanate end with an isocyanate group blocked with ketoimine amine or an aldimine amine, and with an isocyanate group blocked with a secondary amine, a ketoimine amine and / or an aldimine amine is blocked. The present invention for carrying out an exchange reaction with an isocyanate group is essentially different from these proposals in both purpose and method.

[0023]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. [Synthesis of ketoimine amine] Ketoimine amine is obtained by reacting acetone, methyl ethyl ketone, diethyl ketone and methyl n-propyl ketone with ethylenediamine in equimolar amounts at 50 ° C for 10 hours. These ketoimine amines were analyzed by liquid chromatography,
Bisketoimine in which both ends of ethylenediamine reacted with ketone, ketoiminamine in which one end of ethylenediamine reacted with ketone, unreacted ethylenediamine, and unreacted ton were mixed, but 70% or more was ketoiminamine, and this is the following reaction Used for.

[Measurement Method of Logarithmic Viscosity] Polymer 0.075
g is dissolved in 25 ml of N, N-dimethylacetamide. 10 ml of this polymer solution was placed in an Ostwald viscometer, the falling seconds were measured, and the logarithmic viscosity (η
_inh ). η _inh = {ln (t / to)} / C t: polymer solution drop seconds (seconds) to: solvent drop seconds (seconds) C: polymer concentration (g / dl)

[Measurement Method of "Post-Polymerizability"] A polyurethane elastic body solution is cast in water to form a film, and after removing the solvent, it is dried at room temperature under a nitrogen stream for 24 hours. This is an as-cast film. This as-
The cast film that was aged at 45 ° C. for 1 week was used as an aging film, and the difference in η _inh between the as-cast film and the aging film is ΔIVa. Assuming post-processing of as-cast film 1
What was soaked in boiling water for 24 hours at room temperature under a nitrogen stream was used as a boiling water treated film, and the difference in η _inh between the as-cast film and the boiling water treated film was ΔIVb. That is, the larger the value of ΔIV, the greater the “post-polymerizability”, and the smaller the value of ΔIVa / ΔIVb, which is the ratio of ΔIVa and ΔIVb, the smaller the “post-polymerizability” near room temperature and the post-processing. It is a desirable polyurethane elastic body that has a large “post-polymerization” under heating in the process.

Example 1 59.29 g of a polytetramethylene ether glycol having a molecular weight of 1839 was reacted with 12.52 g of 4,4'-diphenylmethane diisocyanate at 105 ° C for 1.5 hours to obtain an isocyanate-terminated prepolymer. This one
After cooling to 0 ° C., N, N-dimethylacetamide 1
Add 25 g to dissolve the polymer. 0.95 g of ethylenediamine and 0.07 g of diethylamine were added to this, N, N-
When a solution dissolved in 25 g of dimethylacetamide is added dropwise with stirring, the viscosity gradually increases. After continuing stirring for 10 minutes as it is, 0.22 g of acetone-ethylenediamine equimolar reaction product and 0.13 g of diethylamine were added to N, N.
-A solution dissolved in 5 g of dimethylacetamide was added to carry out an end-terminating reaction to obtain a polyurethane elastic body solution.
The measurement results are shown in Table 1.

[Table 1]

Example 2 The same procedure as in Example 1 was repeated except that 0.24 g of a methyl ethyl ketone-ethylenediamine equimolar reaction product was used in place of the acetone-ethylenediamine equimolar reaction product as the terminal stopper. The results are shown in Table 1.

Example 3 The procedure of Example 1 was repeated, except that 0.27 g of a diethylketone-ethylenediamine equimolar reaction product was used instead of the acetone-ethylenediamine equimolar reaction product as the terminal stopper. The results are shown in Table 1.

Example 4 The same procedure as in Example 1 was repeated except that 0.27 g of a methyl n-propyl ketone-ethylenediamine equimolar reaction product was used in place of the acetone-ethylenediamine equimolar reaction product as the terminal stopper. . The results are shown in Table 1.

Comparative Example 196.8 g of an N, N-dimethylacetamide solution of the prepolymer obtained in the same manner as in Example was mixed with 1.08 g of ethylenediamine and 0.17 g of diethylamine.
What was dissolved in 30 g of dimethylacetamide is added with rapid stirring. Although the viscosity immediately increases, the stirring speed is reduced and stirring is continued for 10 minutes to obtain a polyurethane elastic body solution. The results are shown in Table 1.

[0031]

EFFECT OF THE INVENTION The polyurethane elastic body obtained by the conventional method has, as an end group, an isocyanate group and an amino group blocked with a secondary amine. Since this exchange reaction between terminal groups occurs even at room temperature, "post-polymerization", which is expected to occur only under heating conditions during the post-processing step, also occurs at room temperature, leading to fluctuations in physical properties. In contrast,
According to the present invention, "post-polymerization" is caused by heating during the post-processing step.
However, since the "post-polymerizability" at room temperature is small, a polyurethane elastic body having excellent physical properties can be easily and stably obtained.

Claims (2)

[Claims] 1. An elastic body containing polyurethane as a main component, which is obtained by using a polyol, a diisocyanate, and a diamine as main reaction components, comprises (a) a secondary monoamine and (b) a ketoimine amine and / or an aldimine amine. A polyurethane elastic body comprising both (a) and (b). 2. A method of producing a polyurethane elastic body by subjecting a prepolymer obtained from a polyol and an excess of organic diisocyanate to a chain extension reaction with an organic diamine to produce (a) a secondary monoamine as a terminal terminating agent, and
(B) A method for producing a polyurethane elastic body, which comprises using ketoimine amine and / or aldoimine amine.